Timing apparatus

ABSTRACT

A timing apparatus for controlling a motor includes a control shaft rotated by the motor and a cam driven by the control shaft. The cam operates a motor switch which controls the motor. The cam is also rotatable a limited amount relative to the control shaft by a solenoid so that when the solenoid is momentarily energized the motor switch will be actuated and the motor will operate. The motor rotates the control shaft which eventually picks up the cam and rotates it to the position where the motor switch is again in a standby condition. At this point, the motor switch shorts out the leads of the motor so that the motor is regeneratively braked and does not over travel.

United States Patent 1 Burzen [451 Feb. 11, 1975 TIMING APPARATUS [75] lnventor:

[73] Assignee: Nordon Industries, Inc., Fenton, Mo.

[22] Filed: Dec. 17, 1973 [21] Appl. No.: 425,525

Norman J. Burzen, Pacific, Mo.

Primary ExaminerB. Dobeck Attorney, Agent, or Firm-Gravely, Lieder & Woodruff [57] ABSTRACT A timing apparatus for controlling a motor includes a control shaft rotated by the motor and a cam driven by the control shaft. The cam operates a motor switch which controls the motor. The cam is also rotatable a limited amount relative to the control shaft by a solenoid so that when the solenoid is momentarily energized the motor switch will be actuated and the motor will operate. The motor rotates the control shaft which eventually picks up the cam and rotates it to the position where the motor switch is again in a standby condition. At this point, the motor switch shorts out the leads of the motor so that the motor is regeneratively braked and does not over travel.

14 Claims, 12 Drawing Figures PATENTEUFEBI 1 s I v 3.866.101

. v sum 10F 3 FIGS PAIENTEUFEB H915 Y 866. 101

SHEET 2 OF- 3 SHEET 30F 3 PATENTEBFEBI 1 ms IVC FIG ll new TIMING APPARATUS BACKGROUND OF THE INVENTION This invention relates in general to timing mechanisms and, more particularly to timing mechanisms which may be activated by the momentary application of power.

Many coin operated machines are activated merely by inserting a coin in the coin slot thereof. The coin normally falls through a coin chute and in so doing momentarily actuates a small switch along the chute. The electrical pulse resulting from the momentaryclosure of the switch triggers a holding solenoid which in turn causes a motor or some other electrically operated device used in the operation of the coin machine to be energized. This motor remains energized and at the end of the cycle closes another switch which causes the holding solenoid to return to its initial position and interrupt the electrical circuit to the motor. Holding solenoids used in such applications contain heavy coils and contacts and are quite expensive.

Moreover, once the circuit to the motor is interrupted, the motor will continue rotating due to inertia. Usually a clutch or friction operated brake is provided to prevent this over-travel, but devices of this nature are complicated and add further to the expense of the coin operated device.

SUMMARY OF THE INVENTION One of the principal objects of the present invention is to provide a timing device which is actuated by a single pulse of power such as an electrical pulse. Another object is to provide a timing device of the type stated which upon receipt of an electrical impulse remains in operation without the aid of a holding solenoid. A further object is to provide a timing device of the type stated which is ideally suited for use in coin operated machines. An additional object is to provide a coin operated device of the type stated wherein over-travel of the motor is avoided without using friction brakes or clutches. Still another object is to provide a timing device of the type stated which is simple in construction and highly reliable. These and other objects and advantages will become apparent hereinafter.

The present invention resides in timing apparatus including a motor, a switch for controlling the motor, and switch actuating means propelled by the motor for closing and opening the switch. The switch actuating means is movable independently of the motor so that the motor can be initially energized by moving the switch actuating means.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur:

FIG. I is a perspective view of a timing apparatus constructed in accordance with an embodying the present invention;

FIG. 2 is an end elevational view of the timing apparatus;

FIG". 3 is a plan view of the timing apparatus in its initial position;

FIG. 4 is a plan view similar to FIG. 3, but showing the solenoid retracted as a result of having received an electrical pulse;

FIG. Sis a plan view similar to FIG. 4 but showing the control shaft rotated so that the drive pin picks up the cam and continues rotating it for the remainder of the revolution;

FIG. 6 is a schematic diagram for circuitry used in the timing apparatus;

FIG. 7 is a plan view of a modified timing apparatus forming part of the present invention; the modified apparatus being in its initial position.

FIG. 8 is an end elevational view of the modified timing apparatus shown in FIG. 7.

FIG. 9 is a plan view of still another modified timing apparatus in its initial position.

FIG. 10 is a plan view of the modified timing apparatus of FIG. 9 immediately after it is advanced out of its initial position by retraction of the solenoid.

FIG. 11 is a sectional view taken along line ll-ll of FIG. 9; and

FIG. 12 is a schematic diagram of a modified electrical circuit for the timing apparatus.

DETAILED DESCRIPTION Referring now to the drawings (FIG. 1), A designates a timing apparatus for controlling a motor M which actually forms part of the apparatus A. The motor M in addition powers or operates some other device such as the product dispensing mechanism of a coin machine. the change dispensing mechanism for such a machine, or merely a switch which controls some other mechanism. In any event, the motor M in most instances is quite small and is preferably operated on low voltage direct current.

Aside from the motor M, the timing apparatus A includes a control shaft 2 which is rotated by the motor M through a suitable gear box 3 so that the angular velocity of the shaft 2 is considerably less than that of the drive shaft for the motor M. The control shaft 2 has a drive disk 4 fixed firmly to it so that the disk 4 and shaft 2 rotate in unison. Projecting axially from the disk 4 are a cam journal 6 and an abutment or dirve pin 8. The former is along the axis of rotation, while the latter is offset radially from that axis.

The drive disk 4 supports and drives a start cam 10 (FIGS. 1-3) having a center bore 12 (FIG. 3) through which the cam journal 6 projects. The cam 10 also has an arcuate groove 14 which receives the drive pin 8, and this groove 14 is configured such that it permits the cam to rotate about 90 relative to the drive disk 4. Of course, as the cam 10 rotates relative to the disk 4, the drive pin 8 moves through the arcuate groove 14. The lobe or raised portion of the cam 10 extends around most of the cam perimeter, but is interrupted by a valley or depression 16, the arcuate span of which is less than that of the arcuate groove 14. In addition to the foregoing, the cam 10 has a connecting pin 18 projecting from it, and this pin is offset radially from the axis of rotation.

The control shaft 2 rotates the cam 10 when the drive pin 8 is against the leading end of the arcuate groove 14, and as the cam 10 rotates it activates a motor switch 20 which is connected to and controls the operation of the motor M (FIG. 6). In particular, the cam 10 as it rotates through one revolution moves the motor switch 20 from a standby condition, wherein the motor M does not operate and its leads are shorted, to an actuated position, wherein the motor M does operate, and then back to the standby conditon. Actually, the

body of the switch 20 is mounted firmly'adjacent to the cam and has a plunger 22 which projects into the path of the cam 10. The plunger 22 is extended when located opposite to the depression 16 and the switch 20 is at standby, but as the cam 10 rotates from that position its lobe engages the plunger 22 and depresses it, thereby actuating the switch 20. Thus, when the depression I6 is opposite the switch plunger 22, the motor M is not energized, but is shorted out.

Also positioned adjacent to the start cam 10 is a solenoid 30 (FIG. 3) having a fixed coil 32 and a shiftable armature 34 which retracts into the coil 32 when the coil 32 is energized. The axis of the solenoid 30 intersects the axis of rotation for the control shaft 2, and also is located at right angles to the radius along which the pin 18 is disposed when the cam 10 is positioned with the drive pin 8 at the leading end of the arcuate groove 14 (FIG. 3). lnterconnecting the armature 34 and the cam 10 is a connecting link 36 which is attached to the former at a pivot pin 38 and to the latter at the connecting pin 18. When the armature 34 is not energized, the connecting pin 18 should be positioned about 90 from the axis of the solenoid (FIG. 3). However, when the solenoid 30 is energized, the connecting pin 18 should be located along the axis of the solenoid 30 (FIG. 4). Thus, the stroke of the armature 34-should be sufficient to rotate the cam 10 through an angle of about 90, and the length of the connecting link 36 should be sufficient to accommodate this movement.

The solenoid 30 is operated by a start switch 40 (FIG. 6) which is connected in series with its coil 32, and that switch 30 is normally open. The series combination of the switch 40 and coil 32 is connected between electrical power lines 42 and 44, across which 120 volts AC exists. The motor M is connected across direct current power lines 46 and 48, across which a suitable voltage exists. The switch 20 is connected in series with motor M and when its plunger 22 is depressed it places the motor M across the lines 46 and 48. On the other hand, when the plunger 22 is extended, that is when it projects into the depression 16 of the cam 10, the switch 20 connects the two leads from the motor M together through the line 48.

Considering now the operation of the timing apparatus A, the cam 10 is initially at rest with its depression 16 opposite the plunger 22 of the switch 20 (FIG. 3) so that motor M is de-energized and its leads are connected together (FIG. 6). This is the initial position for the cam 10. The armature 34 of the solenoid 30 is also extended so that the connecting pin 18 is located 90 from the axis of the solenoid 30 and thelink 36 is disposed at an. angle to the axis of the solenoid 30 (FIG. 3). When the start switch 40 is momentarily closed such as by a coin dropping through a coin chute or by a button being depressed, the solenoid 30 is placed across the 120 V lines 42 and 44 and its armature 34 is drawn into the coil 32 (FIG 4). The armature 34 acting through the link 36 rotates the cam 10 90 away from its initial position so that the connecting pin 18 moves to a position nearly along the axis of the solenoid 30. The drive disk 4, however, remains stationary so that as the cam 10 rotates, the arcuate groove 14 therein moves from a position wherein the drive pin 8 is at its leading end (FIG. 3) to a position wherein the drive pin 8 is at its trailing end (FIG. 4).

Rotation of the start cam 10 through the 90 angle further brings the lobe of the cam 10 against the plunger 22 of the switch 30 so that the plunger22 is depressed (FIG. 4) andthe motor M is placed across the lines 46 and 48. As a result the motor M turns and rotates the control shaft 2 and the drive disk 4 on it. the direction of rotation being the same as that in which the solenoid 30 rotates the cam 10. During the first of rotation, the disk 4 rotates independently of the cam 10, and as it does the drive pin 8 moves in the arcuate groove 14 from the trailing end (FIG. 4) to the leading end thereof (FIG. 5). Once the drive pin 8 reaches the leading end of the groove 14, it rotates the cam 10 so that during the remaining 270 of movement the cam 10 and disk 4 rotate in unison. Since the lobe of the cam 10 exists for this remaining 270, the plunger 22 of the switch 20 remains depressed and the motor M remains energized. As the disk 4 and cam 10 continue to rotate the armature 34 is withdrawn from the coil 32 and brought back to its initial position.

At the end ofa complete rotation for the cam 10 the plunger 22 of the switch 20 runs off of the lobe and drops into the depression 16 (FIG. 3). As a result, the switch 20 disconnects the motor M from the lines 46 and 48 and shorts out the motor M through the line 48. The motor M will continue to rotate due to the inertia of its armature and components rotated therewith and will act as a generator. However, since the generator so formed supplies a very low resistance (a short circuit), the tendency to rotate is greatly impeded and overtravel is insignificant. Thus, over-travel is for all intents and purposes prevented by regenerative braking.

MODIFICATIONS In some instances it is desirable to have the control shaft 2 complete one or more revolutions, depending on the situation. For example, if the motor M drives a change dispensing apparatus for a coin operated dispensing machine which dispenses items worth a nickle each, the motor M may be used to deliver'a nickle change with each revolution of the control shaft 2. Therefore, if a dime is placed in the machine, the motor M should rotate the control shaft 2 one revolution. On the other hand, if a quarter is inserted'into the machine, the motor M should rotate the control shaft 2 through four revolutions to dispense for nickles as change.

A modified timing apparatus B operates in the foregoing manner and is similar to the apparatus A. However, the start cam 10 is of slightly different configuration in that its depression 16 commences at the arcuate groove 14 which opens outwardly. Also, the drive disk 4 is replaced with a sustaining cam 54 having a depression 55. The switch 20 is positioned so that its plunger 22 lies in the path of both the cams l0 and 54. In addition, the connecting link 36 is replaced with a spring 56, and additional electrical circuitry is provided to keep the solenoid 30 energized through a predetermined number of revolutions for the control shaft 2. The sustaining cam 54 has a lober 58 (FIG. 7) which passes by the switch plunger 22 as the depression 16 on the cam 10 is pulled past that plunger 22 by the spring 56, as will be described.

Once the solenoid 30 is energized, its armature 34 retracts and rotates the start cam 10 through 90, the rotating force being transmitted through the spring 56. The motor M will then be energized and will rotate the sustaining cam 54 which will pick up the cam 10 and rotate it after 90 of rotation. The rotation of the cams l0 and 54 through the next 180 will not, however,

withdraw the armature 34 from the coil 32, which remains energized, but instead will expand the spring 56. Once the connecting pin 18 passes somewhat beyond the 270 position, the expanded spring 56 will quickly draw it toward the armature 34 of the solenoid 30,

causing the cam to rotate relative to the sustaining cam 54 as it does. As the depression 16 of the cam 10 passes by the plunger 22 of the motor switch 20, the lobe of the sustaining cam 54 will be opposite the plunger 22 and will keep it'depressed. Thereafter, the lobe of the start cam 10 will again pick up the plunger 22 so that the plunger 22 remains depressed as the depression 55 of the cam 54 is opposite the plunger 22.

After the commencement of the last revolution of the shaft 2 and cam 54, the solenoid 30 is de-energized. Thus, the solenoid 30 still rotates the cam 10 through the first 90 of the last revolution, but thereafter has no further affect. In other words, the spring 56' does not expand during the subsequent 180 of movement for the cam 10 and therefore cannot draw the cam 10 around again. Instead, the spring 56 remains contracted and merely withdraws the armature 34 from the coil 32. Moreover, the pin 18 drives the start cam 10 through its last 90 and once the depression 55 of the sustaining cam 54 is located opposite the switch plunger 22, the motor M is de-energized and the sustaining cam 54 stops rotating. The lobe 58 on the start cam 10 at this time is located behind the plunger 22 and does not prevent it from entering the depression 55 on the sustaining cam 54.

In another modified form C of the invention (FlGS. 9-ll), the motor M rotates a control shaft 60 having a drive pin 62 fixed rigidly thereto and projecting radially therefrom. The shaft 60 also carries a start cam 64 having a starting pin 66 projecting from one side in the axial direction for engagement with the drive pin 62. The starting pin 66 is offset from the axis of rotation. The peripheryof the start cam 64 is for the most part a lobe, but this lobe is interrupted by a depression 70 (FIGS. 9 and 10).

The start cam 64 operates a switch 72 having a follower arm 74 which follows the periphery of the cam 64. When the arm 74 is ,in the depression 70, the switch 72 is at standby and the motor M is de-energized. This is the start or initial position (FIG. 9).

The initial movementof the cam 64 is derived from a solenoid 76 having an armature 78 connected to a spring wire 82 which extends across the cam 64 and is pivoted on the other side about a pivot 84. When the start cam 64 is in its initial position, the pin 66 will be located against the spring wire 82 and the drive pin 62 will be immediately behind the start pin 66 (FIG. 9).

When the solenoid 76 is energized by the momentary closure of a switch connected thereto, its armature 78 retracts and drives the spring wire 82 against the start pin 66 (FIG. 10). This causes the start cam 64 to rotate about 60, just far enough to move the follower arm 74 of the switch 72 out of the depression 70 and onto the lobe of the cam 64. Thus, the initial rotationeffected by the solenoid 76 results in a closure of the switch 72 which in turn energizes the motor M. The motor M turns the control shaft 60 in the same direction as the cam 64 and after about 60 of rotation, the radial drive pin 62 bears against the axial start pin 66 and carries that start pin 66 around along with the start cam 64 of which it forms a part. After a complete revolution, the depression 70 returns to the follower arm 74 and the switch 72 returns to its standby condition. The motor at this point is stopped by regenerative braking, provided it is a direct current motor.

Normally, the weight of the armature 78 causes it to return to its extended position after the solenoid is deenergized. However, if the residual magnetism of the armature 78 retains it in the retracted position, the start pin 66 will engage the spring wire 82 during the last 90 of rotation for the cam 64 and will move the wire 82 away from the axis of rotation for the cam 64. thus withdrawing the armature 34 of the solenoid 30 to its extended position.

By including an additional start pin 66 and depression on the start cam 64 such that the pins 66 and depressions 70 are spaced l apart, the timing apparatus C may be utilized to stop the motor M twice for each complete revolution of the cam 64 and control shaft 2.

Aside from controlling its own motor M, the timing apparatus may be used to control a different and larger motor N (FIG. 12) such as the type used to power a childrens ride or to power the washing equipment of a drive-in type car wash installation. ln such an instance, it is desirable to connect the motor M. in parallel with the motor N and to connect the parallel grouping of motors M and N in series with the motor switch 20 across power lines and 92 which may be volts AC. When the motor switch 20 is in its standby condition, that is when the plunger 22 is extended into a cam depression, it is normally closed as to a coinholding circuit which also includes a start switch 94 and a coin return electromagnet 96. The start switch 94 is also normally closed as to the coin-holding circuit so that normally the coin return electromagnet 96 is energized. The start switch 94 at its normally open contact is connected to the solenoid coil 32 so that when the switch 94 is actuated the solenoid 30 is energized. the current flowing through the solenoid coil 32, the start switch 94 and the motor switch 20. The solenoid 30, when energized turns the start cam 10 and its depresses the plunger 22 of the start switch 20, causing the switch 20 to break the coin-holding circuit and place the motors M and N across the lines 90 and 92. The motors M and N operate until the plunger 22 of the switch 20 is released by the start cam 10 and the switch 20 returns to its standby condition.

This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes ofthe disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

l.-A timing apparatus comprising: a motor; a switch for controlling the motor, the switch having a standby condition wherein the motor does not operate and an actuated condition wherein the motor does operate; a shaft rotated by the motor; switch actuating means rotated in one direction away from an initial position for causing the switch to change from its standby condition to its actuated condition and for thereafter permitting the switch to change back to its standby condition, the switch actuating means being rotatable independently of the shaft in said one direction and also rotatable by the shaft in said one direction; an abutment fixed rigidly with respect to the shaft and engageable with the switch actuating means for enabling the shaft to rotate the switch actuating means when the abutment is engaged therewith; and starting means for rotating the switch actuating means a limited amount in said one direction to change the switch from its standby to its actuated condition, whereby the motor will be energized and will propel the switch actuating means back toward its initial position wherein the switch may again be in its standby condition.

2. A timing apparatus according to claim 1 wherein the switch actuating means is a cam against which the abutment bears.

3. A timing apparatus according to claim 1 wherein the starting means includes a solenoid which initially turns the switch actuating means away from the position in which the abutment is engaged with the switch actuating means.

4. A timing apparatus according to claim 2 wherein the starting means comprises a solenoid, a spring element interconnecting the solenoid and the cam at a location offset from the axis of rotation for the cam so that when the solenoid is energized the cam rotates, and another cam for also operating the switch when the spring rotates the first cam.

5. A timing apparatus comprising: a motor; a switch for controlling the motor, the switch having a standby condition wherein the motor does not operate and an actuated condition wherein the motor does operate; a shaft rotated by the motor; an abutment fixed in position with respect to and rotated by the shaft; a cam rotatable in one direction away from an initial position for causing the switch to change from its standby condition to its actuated condition and for thereafter permitting the switch to change back to its standby condition, the cam being positioned such that the abutment will bear against it as the shaft rotates, the cam being rotatable independently of the shaft in said one direction and further being rotatable with the shaft in said one direction when the abutmentbears against the cam; and starting means for rotating the cam a limited amount in said one direction to change the switch from its standby to its actuated condition, whereby the motor will be energized and will rotate the cam back toward its initial position wherein the switch may again be in its standby condition.

6. A timing apparatus according'to claim 5 wherein the starting means comprises a solenoid which when energized rotates the cam relative to the shaft in the direction which causes the abutment to be positioned away from the position in which it will propel the cam, whereby the switch is changed from its standby to its actuated condition and the motor is energized to bring the abutment again to a position in which it will propel the cam.

7. A timing apparatus according to claim 5 wherein the abutment is a pin extending in the direction of the axis of rotation for the shaft but offset radially therefrom and wherein the cam has an arcuated groove which os concentric about the azis of rotation and receives the pin, whereby the cam can rotate a limited amount independently of the shaft.

8. A timing apparatus according to claim 5 wherein the abutment projects in the radial direction relative to the axis of rotation and the cam has an axially extend- 10. A timing apparatus according to claim 8 wherein the starting means includes an elongated element ex tended across the cam and pivoted at one end, the element being positioned to engage the axial member and rotate the cam when moved about its pivot, and a solenoid connected to the elongated element for moving it about its pivot.

11. A timing apparatus comprising a motor,.a control shaft coupled with and propelled by the motor, a cam rotatable relative to the control shaft about the axis of rotation for the control shaft, drive means carried by the control-shaft for engaging the cam and rotating it as the control shaft rotates, a switch moved from a standby condition to an actuating condition and then back to the standby condition by the cam as the cam rotates, the switch being connected to the motor for controlling the operation thereof, and a solenoid connected to the cam suchthat it will turn the cam when momentarily energized, whereby the motor will be energized and will cause the control shaft to drive the cam back to the position in which theswitch is in its standby condition. 7

12. A timing apparatus comprising: a motor; switch means for controlling the motor, the switch means having a standby condition wherein the motor does not op erate and an actuated condition wherein the motor does operate; a control shaft coupled with and rotated by the motor in one direction; a first cam mounted rigidly on the control shaft for rotation therewith in said one direction; a second cam rotatable relative 'to.the first cam for movement in said one direction away from an engaged position wherein rotation of the first cam in said one direction is transmitted to the second cam to enable the cams to rotate in unison; the first cam being at an initial position and the second cam being substantially at its engaged position when the switch means is in its standby condition, the first cam being configured to operate the switch means to change it to its actuated condition when rotated awayfrom the intitial position, the second cam being configured to operate the switch means to change it to its actuated condition when rotated in said one direction away from its engagedposition when the first cam is in its initial posiing member which is offset from the axis of rotation tion; and starting means connected to the second cam for rotating the second cam in said one direction away from its engaged position when the first cam is in its initial position, whereby the switch means will change to its actuated condition and the motor will be energized to rotate the first cam in said one direction, thus causing the second cam to again assume its engaged position relative the first cam so that the two cams will rotate in unison toward the initial position for. the first cam.

13. A timing apparatus according to claim 12 wherein the starting means comprises a movable element which moves toward and away from the axis of rotation for the shaft, and a spring means coupling the movable element with the second cam, whereby when the movable element maintains the spring means in a distorted condition, the second cam will move away from its engaged position as the first cam approaches its initial position so that the control shaft will continue to rotate and will move the first cam through its initial position without stopping the control shaft.

14. A timing apparatus according to claim 13 wherein the movable element is an armature which is moved by a solenoid coil. 

1. A timing apparatus comprising: a motor; a switch for controlling the motor, the switch having a standby condition wherein the motor does not operate and an actuated condition wherein the motor does operate; a shaft rotated by the motor; switch actuating means rotated in one direction away from an initial position for causing the switch to change from its standby condition to its actuated condition and for thereafter permitting the switch to change back to its standby condition, the switch actuating means being rotatable independently of the shaft in said one direction and also rotatable by the shaft in said one direction; an abutment fixed rigidly with respect to the shaft and engageable with the switch actuating means for enabling the shaft to rotate the switch actuating means when the abutment is engaged therewith; and starting means for rotating the switch actuating means a limited amount in said one direction to change the switch from its standby to its actuated condition, whereby the motor will be energized and will propel the switch actuating means back toward its initial position wherein the switch may again be in its standby condition.
 2. A timing apparatus according to claim 1 wherein the switch actuating means is a cam against which the abutment bears.
 3. A timing apparatus according to claim 1 wherein the starting means includes a solenoid which initially turns the switch actuating means away from the position in which the abutment is engaged with the switch actuating means.
 4. A timing apparatus according to claim 2 wherein the starting means comprises a solenoid, a spring element interconnecting the solenoid and the cam at a location offset from the axis of rotation for the cam so that when the solenoid is energized the cam rotates, and another cam for also operating the switch when the spring rotates the first cam.
 5. A timing apparatus comprising: a motor; a switch for controlling the motor, the switch having a standby condition wherein the motor does not operate and an actuated condition wherein the motor does operate; a shaft rotated by the motor; an abutment fixed in position with respect to and rotated by the shaft; a cam rotatable in one direction away from an initial position for causing the switch to change from its standby condition to its actuated condition and for thereafter permitting the switch to change back to its standby condition, the cam being positioned such that the abutment will bear against it as the shaft rotates, the cam being rotatable independently of the shaft in said one direction and further being rotatable with the shaft in said one direction when the abutment bears against the cam; and starting means for rotating the cam a limited amount in said one direction to change the sWitch from its standby to its actuated condition, whereby the motor will be energized and will rotate the cam back toward its initial position wherein the switch may again be in its standby condition.
 6. A timing apparatus according to claim 5 wherein the starting means comprises a solenoid which when energized rotates the cam relative to the shaft in the direction which causes the abutment to be positioned away from the position in which it will propel the cam, whereby the switch is changed from its standby to its actuated condition and the motor is energized to bring the abutment again to a position in which it will propel the cam.
 7. A timing apparatus according to claim 5 wherein the abutment is a pin extending in the direction of the axis of rotation for the shaft but offset radially therefrom and wherein the cam has an arcuated groove which os concentric about the azis of rotation and receives the pin, whereby the cam can rotate a limited amount independently of the shaft.
 8. A timing apparatus according to claim 5 wherein the abutment projects in the radial direction relative to the axis of rotation and the cam has an axially extending member which is offset from the axis of rotation and is engaged by the abutment.
 9. A timing apparatus according to claim 8 wherein the starting means also engages the axially extending member.
 10. A timing apparatus according to claim 8 wherein the starting means includes an elongated element extended across the cam and pivoted at one end, the element being positioned to engage the axial member and rotate the cam when moved about its pivot, and a solenoid connected to the elongated element for moving it about its pivot.
 11. A timing apparatus comprising a motor, a control shaft coupled with and propelled by the motor, a cam rotatable relative to the control shaft about the axis of rotation for the control shaft, drive means carried by the control shaft for engaging the cam and rotating it as the control shaft rotates, a switch moved from a standby condition to an actuating condition and then back to the standby condition by the cam as the cam rotates, the switch being connected to the motor for controlling the operation thereof, and a solenoid connected to the cam such that it will turn the cam when momentarily energized, whereby the motor will be energized and will cause the control shaft to drive the cam back to the position in which the switch is in its standby condition.
 12. A timing apparatus comprising: a motor; switch means for controlling the motor, the switch means having a standby condition wherein the motor does not operate and an actuated condition wherein the motor does operate; a control shaft coupled with and rotated by the motor in one direction; a first cam mounted rigidly on the control shaft for rotation therewith in said one direction; a second cam rotatable relative to the first cam for movement in said one direction away from an engaged position wherein rotation of the first cam in said one direction is transmitted to the second cam to enable the cams to rotate in unison; the first cam being at an initial position and the second cam being substantially at its engaged position when the switch means is in its standby condition, the first cam being configured to operate the switch means to change it to its actuated condition when rotated away from the intitial position, the second cam being configured to operate the switch means to change it to its actuated condition when rotated in said one direction away from its engaged position when the first cam is in its initial position; and starting means connected to the second cam for rotating the second cam in said one direction away from its engaged position when the first cam is in its initial position, whereby the switch means will change to its actuated condition and the motor will be energized to rotate the first cam in said one direction, thus causing the second cam to again assume its engaged position relative the first cam so that the two cams will rotate in unison toward the initial position for the first cam.
 13. A timing apparatus according to claim 12 wherein the starting means comprises a movable element which moves toward and away from the axis of rotation for the shaft, and a spring means coupling the movable element with the second cam, whereby when the movable element maintains the spring means in a distorted condition, the second cam will move away from its engaged position as the first cam approaches its initial position so that the control shaft will continue to rotate and will move the first cam through its initial position without stopping the control shaft.
 14. A timing apparatus according to claim 13 wherein the movable element is an armature which is moved by a solenoid coil. 